US20100133088A1 - Method for the chemical depolymerization of waste polyethylene terephthalate - Google Patents

Method for the chemical depolymerization of waste polyethylene terephthalate Download PDF

Info

Publication number
US20100133088A1
US20100133088A1 US12/452,630 US45263008A US2010133088A1 US 20100133088 A1 US20100133088 A1 US 20100133088A1 US 45263008 A US45263008 A US 45263008A US 2010133088 A1 US2010133088 A1 US 2010133088A1
Authority
US
United States
Prior art keywords
depolymerization
stage
microwave radiation
carried out
acid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/452,630
Inventor
Milan Hajek
Jiri Sobek
Jaroslav Brustman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Institute of Chemical Process Fundamentals CAS
Original Assignee
Institute of Chemical Process Fundamentals CAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Institute of Chemical Process Fundamentals CAS filed Critical Institute of Chemical Process Fundamentals CAS
Assigned to USTAV CHEMICKYCH PROCESU AKADEMIE VED CESKE REPUBLIKY reassignment USTAV CHEMICKYCH PROCESU AKADEMIE VED CESKE REPUBLIKY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BRUSTMAN, JAROSLAV, HAJEK, MILAN, SOBEK, JIRI
Publication of US20100133088A1 publication Critical patent/US20100133088A1/en
Abandoned legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/09—Preparation of carboxylic acids or their salts, halides or anhydrides from carboxylic acid esters or lactones
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
    • C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
    • C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
    • C08J11/24—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds containing hydroxyl groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the invention relates to a method for the chemical depolymerization of polyethylene terephthalate (PET), in particular in the form of PET bottles, by application of microwave radiation and solvolysis in the presence of a catalyst into appropriate monomers, i.e. terephthalic acid, or its derivatives, and ethylene glycol.
  • PET polyethylene terephthalate
  • a catalyst into appropriate monomers, i.e. terephthalic acid, or its derivatives, and ethylene glycol.
  • the driving force behind the PET bottles recycling is the accumulated waste PET material produced by the beverage industry.
  • the majority of PET bottles are processed into fibres.
  • the chemical depolymerization which is especially advantageous in the case of heavily contaminated PET material, is based on the solvolysis and includes most frequently hydrolysis, methanolysis, glycolysis, or potentially ammonolysis i.e. processes by which monomers that can be used for the synthesis of new PET products are formed.
  • the PET material depolymerization by the effect of microwave radiation under atmospheric pressure was recently described by Egyptian authors in the journal of Advances of Polymer Technology 25, 242-246 (2006).
  • the paper describes hydroglycolysis carried out in excess of C 2 -C 6 alcohols in the presence of basic catalysts (sodium hydroxide, potassium hydroxide) and sodium and zinc acetate, respectively.
  • the material subjected to the depolymerization reaction was a pure PET material, which was easy to get depolymerized even without any microwave radiation present (100° C., 30 min, 100% conversion) and not a waste PET.
  • the Czech patent CZ 296343 describes the acidic hydrolysis of waste PET material by means of strong acids such as nitric acid or perchloric acid, or mixtures thereof, by the effect of microwave radiation.
  • the hydrolysis was apparently carried out under elevated pressure but the ethylene glycol formed was completely destructed.
  • the primary object of the invention is to provide a method for the chemical depolymerization of polyethylene terephthalate by application of microwave radiation and solvolysis in the presence of a catalyst.
  • the waste polyethylene terephthalate is mixed up with an microwaves absorbing activator, the mixture is melted by its exposing to a microwave radiation on a frequency from 915 to 2450 MHz and with a power output from 0.1 to 0.5 kW per kg of a charge, at a temperature from 230 to 330° C., under atmospheric pressure and in the second stage, the molten mixture is subjected to solvolysis, including acidic or basic hydrolysis, alcoholysis or glycolysis in the presence of a catalyst under continuing microwave radiation and atmospheric pressure yielding terephthalic acid, salts or esters thereof, and ethylene glycol.
  • tungsten carbide As an activator silicon carbide, tungsten carbide, ferrite, magnetite, active carbon, or polar liquids as alcohols (methanol, ethanol) diols (ethylene glycol, propylene glycol), ketones (acetone, acetophenone), acids (p-toluene sulphonic acid, terephthalic acid, formic acid, or acetic acid), or water and their mixtures at the amount of 1-30% by weight based on the PET raw material may be employed.
  • alcohols methanol, ethanol diols (ethylene glycol, propylene glycol), ketones (acetone, acetophenone), acids (p-toluene sulphonic acid, terephthalic acid, formic acid, or acetic acid), or water and their mixtures at the amount of 1-30% by weight based on the PET raw material
  • ketones acetone, acetophenone
  • acids p-toluene sulphonic acid, tere
  • the acidic hydrolysis may be carried out in the presence of acidic catalysts, for instance heterogeneous catalysts as montmorillonites K10 and KSF, ion exchangers, zeolites, phosphoric acid supported on alumina or silica, furthermore, copper(II), iron(III), zinc(II), aluminium(III), antimony(III), bismuth(III) chlorides or acetates, respectively, or using homogeneous catalysts as p-toluene sulphonic, formic, acetic, benzoic, terephthalic, or sulphuric acid, respectively.
  • acidic catalysts for instance heterogeneous catalysts as montmorillonites K10 and KSF, ion exchangers, zeolites, phosphoric acid supported on alumina or silica, furthermore, copper(II), iron(III), zinc(II), aluminium(III), antimony(III), bismuth(III) chlorides or acetates, respectively, or using homogene
  • the alkaline hydrolysis may be carried out in the presence of strong bases such as alkaline metal hydroxide (sodium hydroxide, potassium or lithium hydroxide, respectively), or potentially in the presence of phase transfer catalysts, for example TOMAB (trioctyl methyl ammonium bromide).
  • strong bases such as alkaline metal hydroxide (sodium hydroxide, potassium or lithium hydroxide, respectively)
  • phase transfer catalysts for example TOMAB (trioctyl methyl ammonium bromide).
  • the alcoholysis may be carried out in the presence of alcohol such as methanol or ethanol, or diol such as ethylene glycol and transesterification catalysts in particular zinc(II) or ferric(III) chloride, or manganese(II), cobalt(II), calcium(II), and magnesium (II) acetates, respectively.
  • alcohol such as methanol or ethanol
  • diol such as ethylene glycol and transesterification catalysts in particular zinc(II) or ferric(III) chloride, or manganese(II), cobalt(II), calcium(II), and magnesium (II) acetates, respectively.
  • the depolymerization may be carried out in the presence of ionic liquid being added in the second stage of the depolymerization.
  • the molten mixture may be exposed to a microwave radiation at a temperature between 100 and 220° C. and in both the first and the second stage the depolymerization may be carried out in air or in inert atmosphere of nitrogen or argon, in either a batch or continuous process.
  • Molten and partially depolymerised PET material may be transferred either directly into an solvolytic solution, where it undergoes hydrolysis or alcoholysis, or it may be left to solidify and be crushed or shredded into grain 0.1 to 2 mm in size prior to being transferred into the second stage.
  • microwave technology presents very energy saving technique in order of magnitude from 30 to 50% of the electric energy consumption compared with classic methods of the thermal depolymerization and provides valuable resulting products, which then can be directly used or be subject to further easy processing.
  • the molten and partially depolymerised PET material is then discharged into a solvolytic reactor containing water or a solution of alkaline hydroxide, or acid, and the depolymerization is completed in the microwave oven under microwave radiation in the presence of a solvolytic catalyst yielding ethylene glycol, terephthalic acid, or derivatives thereof.
  • Ethylene glycol is then separated by distillation under reduced pressure and terephthalic acid and its derivatives are separated by conventional processes, i.e. by acid filtration and esters distillation.
  • the process of melting waste PET material is conducted under the same conditions as in example 1 except that as the melting activator 20 wt % silicon carbide, tungsten carbide, ferrite, magnetite, active carbon or polar liquids as alcohols (methanol, ethanol), diols (ethylene glycol, propylene glycol), ketones (acetone, acetophenone), acids (p-toluene sulphonic, terephthalic, formic, and acetic acid, respectively), water and their mixtures is subsequently used.
  • the melt is then withdrawn from the bottom outlet and continuously refilled through the upper inlet.
  • the melt is added to a solvolytic solution or it can be left to solidify and after being crushed to grain 0.1 to 2.0 mm in size subjected to the depolymerization in the second stage.
  • the acidic hydrolysis according to the example 3 is carried out in the second stage on the same conditions under the microwave radiation except that in the second stage iron(III) chloride is replaced subsequently with montmorillonite K10 and KSF, ion exchangers, zeolites, phosphoric acid supported on alumina or silica, furthermore, with chlorides or acetates of copper(II), iron(III), zinc(II), aluminium(III), antimony (III), bismuth(III), or homogeneous catalysts as p-toluene sulphonic acid, formic acid, acetic acid, benzoic acid, terephthalic acid, or sulphuric acid, and ionic liquids, respectively.
  • iron(III) chloride is replaced subsequently with montmorillonite K10 and KSF, ion exchangers, zeolites, phosphoric acid supported on alumina or silica, furthermore, with chlorides or acetates of copper(II), iron(III), zinc(
  • 20 g crushed waste PET material as in example 2 undergoes the alkaline hydrolysis in the mixture of 50 ml water and 10 g lithium hydroxide, or potentially sodium or potassium hydroxide and a phase transfer catalyst, for example TOMAB (trioctyl methyl ammonium bromide).
  • a phase transfer catalyst for example TOMAB (trioctyl methyl ammonium bromide).
  • TOMAB trioctyl methyl ammonium bromide
  • the invention can be used for the solution of the problems of accumulated waste, in particular waste based on PET bottles, by way of its total depolymerization into monomers, i.e. ethylene glycol and terephthalic acid, or derivatives thereof, and the reuse thereof for the PET bottle production.
  • monomers i.e. ethylene glycol and terephthalic acid, or derivatives thereof

Abstract

A method for the chemical depolymerization of waste polyethylene terephthalate by application of microwave radiation and solvolysis in the presence of a catalyst comprising the first stage where the waste polyethylene terephthalate is mixed up with an microwaves absorbing activator, the mixture is melted by its exposing to a microwave radiation on a frequency from 915 to 2450 MHz and with a power output from 0.1 to 0.5 kW per kg of a charge, at a temperature from 230 to 330° C., under atmospheric pressure and the second stage, where the molten mixture is subjected to solvolysis, including acidic or basic hydrolysis, alcoholysis or glycolysis in the presence of a catalyst under continuing microwave radiation and atmospheric pressure yielding terephthalic acid, salts or esters thereof, and ethylene glycol.

Description

    TECHNICAL FIELD
  • The invention relates to a method for the chemical depolymerization of polyethylene terephthalate (PET), in particular in the form of PET bottles, by application of microwave radiation and solvolysis in the presence of a catalyst into appropriate monomers, i.e. terephthalic acid, or its derivatives, and ethylene glycol.
    • BACKGROUND ART
  • The recycling of waste polyethylene terephthalate, especially PET bottles, is currently one of the most important tasks in the polymers recycling industry. The driving force behind the PET bottles recycling is the accumulated waste PET material produced by the beverage industry. At present, the majority of PET bottles are processed into fibres. Because of troubles in the use of waste PET bottles for the production of fresh PET bottles in so-called “bottle to bottle” technology and insufficient sorting the chemical processing of waste PET bottles into monomers is becoming more attractive. The chemical depolymerization, which is especially advantageous in the case of heavily contaminated PET material, is based on the solvolysis and includes most frequently hydrolysis, methanolysis, glycolysis, or potentially ammonolysis i.e. processes by which monomers that can be used for the synthesis of new PET products are formed.
  • These methods include hydrolysis using acids or bases in the aqueous medium, U.S. Pat. No. 4,355,175, alcoholysis or glycolysis in the presence of various catalysts, Journal of Applied Polymer Science 34, 235 (1989), or potentially hydrolysis or alcoholysis in the supercritical medium, U.S. Pat. No. 4,605,762. However, all these aforementioned methods require harsh reaction conditions such as the use of strong acids or bases, high temperature, and in particular, elevated pressure. U.S. Pat. No. 3,544,622, EP 597751, and EP 587751/and Czech patents CZ 288622, CZ 296280 also deal with the chemical recycling of the waste PET material.
  • It is known that using microwave radiation as an energy source in chemical reactions increased rate of reaction, i.e. reduced reaction time and higher product yield may be achieved even under milder reaction conditions. Recently, a PET material depolymerization using for the alcoholysis (methanol, propylene glycol, polyethylene glycol) microwave radiation was described in the patent SI 9800060. The depolymerization was performed under elevated pressure in the presence of zinc acetate as a catalyst. Likely, Chinese patents CN 1401688 and CN 1594268 describe the PET material depolymerization in the presence of microwave radiation by using only water without catalyst, but under high pressure (20 bar) and temperature (220-230° C.)
  • The PET material depolymerization by the effect of microwave radiation under atmospheric pressure was recently described by Iranian authors in the journal of Advances of Polymer Technology 25, 242-246 (2006). The paper describes hydroglycolysis carried out in excess of C2-C6 alcohols in the presence of basic catalysts (sodium hydroxide, potassium hydroxide) and sodium and zinc acetate, respectively. However, the material subjected to the depolymerization reaction was a pure PET material, which was easy to get depolymerized even without any microwave radiation present (100° C., 30 min, 100% conversion) and not a waste PET. The Czech patent CZ 296343 describes the acidic hydrolysis of waste PET material by means of strong acids such as nitric acid or perchloric acid, or mixtures thereof, by the effect of microwave radiation. The hydrolysis was apparently carried out under elevated pressure but the ethylene glycol formed was completely destructed.
    • DISCLOSURE OF INVENTION
  • The primary object of the invention is to provide a method for the chemical depolymerization of polyethylene terephthalate by application of microwave radiation and solvolysis in the presence of a catalyst. Specifically, in the first stage the waste polyethylene terephthalate is mixed up with an microwaves absorbing activator, the mixture is melted by its exposing to a microwave radiation on a frequency from 915 to 2450 MHz and with a power output from 0.1 to 0.5 kW per kg of a charge, at a temperature from 230 to 330° C., under atmospheric pressure and in the second stage, the molten mixture is subjected to solvolysis, including acidic or basic hydrolysis, alcoholysis or glycolysis in the presence of a catalyst under continuing microwave radiation and atmospheric pressure yielding terephthalic acid, salts or esters thereof, and ethylene glycol.
  • Other aspects of the method according to the invention are apparent from the hereinafter described or detailed potential specific embodiments thereof.
  • As an activator silicon carbide, tungsten carbide, ferrite, magnetite, active carbon, or polar liquids as alcohols (methanol, ethanol) diols (ethylene glycol, propylene glycol), ketones (acetone, acetophenone), acids (p-toluene sulphonic acid, terephthalic acid, formic acid, or acetic acid), or water and their mixtures at the amount of 1-30% by weight based on the PET raw material may be employed.
  • The acidic hydrolysis may be carried out in the presence of acidic catalysts, for instance heterogeneous catalysts as montmorillonites K10 and KSF, ion exchangers, zeolites, phosphoric acid supported on alumina or silica, furthermore, copper(II), iron(III), zinc(II), aluminium(III), antimony(III), bismuth(III) chlorides or acetates, respectively, or using homogeneous catalysts as p-toluene sulphonic, formic, acetic, benzoic, terephthalic, or sulphuric acid, respectively.
  • Alternatively, the alkaline hydrolysis may be carried out in the presence of strong bases such as alkaline metal hydroxide (sodium hydroxide, potassium or lithium hydroxide, respectively), or potentially in the presence of phase transfer catalysts, for example TOMAB (trioctyl methyl ammonium bromide).
  • The alcoholysis may be carried out in the presence of alcohol such as methanol or ethanol, or diol such as ethylene glycol and transesterification catalysts in particular zinc(II) or ferric(III) chloride, or manganese(II), cobalt(II), calcium(II), and magnesium (II) acetates, respectively.
  • The depolymerization may be carried out in the presence of ionic liquid being added in the second stage of the depolymerization.
  • In the second stage of the depolymerization process, the molten mixture may be exposed to a microwave radiation at a temperature between 100 and 220° C. and in both the first and the second stage the depolymerization may be carried out in air or in inert atmosphere of nitrogen or argon, in either a batch or continuous process.
  • The melting process runs at high rate in the whole bulk volume and the shape of the feed material has no influence on the melting rate. Molten and partially depolymerised PET material may be transferred either directly into an solvolytic solution, where it undergoes hydrolysis or alcoholysis, or it may be left to solidify and be crushed or shredded into grain 0.1 to 2 mm in size prior to being transferred into the second stage.
  • The combination of microwave technology and the methods according to the invention, including application of an activator, presents very energy saving technique in order of magnitude from 30 to 50% of the electric energy consumption compared with classic methods of the thermal depolymerization and provides valuable resulting products, which then can be directly used or be subject to further easy processing.
    • MODE(S) FOR CARRYING OUT THE INVENTION Example 1
  • 2 kg waste polyethylene terephthalate containing 7 wt % impurities is mixed with an activator represented by 10% acetic acid in a 10:1 ratio. The resulting mixture is fed into a ceramic crucible provided with a bottom discharge valve and the crucible is placed into a microwave oven lined with insulating material permeable for microwave radiation. Then the mixture in the crucible is exposed to microwave radiation on a frequency of 2450 MHz and with a power output of 0.7 kW for the period of 30 minutes at a temperature of 250° C. until the mixture material is molten. The molten and partially depolymerised PET material is then discharged into a solvolytic reactor containing water or a solution of alkaline hydroxide, or acid, and the depolymerization is completed in the microwave oven under microwave radiation in the presence of a solvolytic catalyst yielding ethylene glycol, terephthalic acid, or derivatives thereof. Ethylene glycol is then separated by distillation under reduced pressure and terephthalic acid and its derivatives are separated by conventional processes, i.e. by acid filtration and esters distillation.
    • Example 2
  • The process of melting waste PET material is conducted under the same conditions as in example 1 except that as the melting activator 20 wt % silicon carbide, tungsten carbide, ferrite, magnetite, active carbon or polar liquids as alcohols (methanol, ethanol), diols (ethylene glycol, propylene glycol), ketones (acetone, acetophenone), acids (p-toluene sulphonic, terephthalic, formic, and acetic acid, respectively), water and their mixtures is subsequently used. The melt is then withdrawn from the bottom outlet and continuously refilled through the upper inlet. The melt is added to a solvolytic solution or it can be left to solidify and after being crushed to grain 0.1 to 2.0 mm in size subjected to the depolymerization in the second stage.
    • Example 3
  • In the second stage, 20 g crushed PET material prepared according to example 2 is subjected to acidic hydrolysis in the mixture of 40 ml water and 10 g iron(III) chloride. The reaction mixture is exposed to microwave radiation in a microwave oven in the nitrogen atmosphere and maintained at its boiling point. 83% conversion into terephthalic acid and ethylene glycol is achieved in 90 minutes.
    • Example 4
  • The acidic hydrolysis according to the example 3 is carried out in the second stage on the same conditions under the microwave radiation except that in the second stage iron(III) chloride is replaced subsequently with montmorillonite K10 and KSF, ion exchangers, zeolites, phosphoric acid supported on alumina or silica, furthermore, with chlorides or acetates of copper(II), iron(III), zinc(II), aluminium(III), antimony (III), bismuth(III), or homogeneous catalysts as p-toluene sulphonic acid, formic acid, acetic acid, benzoic acid, terephthalic acid, or sulphuric acid, and ionic liquids, respectively.
    • Example 5
  • 20 g crushed waste PET material as in example 2 undergoes the alkaline hydrolysis in the mixture of 50 ml water and 10 g lithium hydroxide, or potentially sodium or potassium hydroxide and a phase transfer catalyst, for example TOMAB (trioctyl methyl ammonium bromide). At a temperature of 106° C., 91% conversion into the corresponding salt of terephthalic acid and ethylene glycol is achieved in 60 minutes.
    • Example 6
  • 20 g crushed waste PET material as in example 2 undergoes the alcoholysis in the presence of 20 ml methanol and 20 g zinc(II) chloride. At the boiling temperature of the reaction mixture, 95% conversion into methyl ester of terephthalic acid and ethylene glycol is achieved within 60 minutes.
    • Example 7
  • The process of alcoholysis according to example 6 is carried out in the presence of ethanol or ethylene glycol under the same conditions with the exception that zinc(II) chloride is replaced by iron(III) chloride, or manganese(II), cobalt(II), calcium(II), and magnesium(II) acetate, respectively.
    • INDUSTRIAL APPLICABILITY
  • The invention can be used for the solution of the problems of accumulated waste, in particular waste based on PET bottles, by way of its total depolymerization into monomers, i.e. ethylene glycol and terephthalic acid, or derivatives thereof, and the reuse thereof for the PET bottle production.

Claims (9)

1. A method of the chemical depolymerization of waste polyethylene terephthalate by application of microwave radiation and solvolysis in the presence of a catalyst wherein in the first stage the waste polyethylene terephthalate is mixed up with a microwaves absorbing activator, the mixture is melted by its exposing to a microwave radiation on a frequency from 915 to 2450 MHz and with a power output from 0.1 to 0.5 kW per kg of a charge, at a temperature from 230 to 330° C., under atmospheric pressure and in the second stage, the molten mixture is subjected to solvolysis, including acidic or basic hydrolysis, alcoholysis or glycolysis in the presence of a catalyst and under continuing microwave radiation and atmospheric pressure yielding terephthalic acid, salts or esters thereof, and ethylene glycol.
2. The method according to claim 1, wherein the activator is selected from the group consisting of silicon carbide, tungsten carbide, ferrite, magnetite, active carbon, or polar liquids as alcohols (methanol, ethanol) diols (ethylene glycol, propylene glycol), ketones (acetone, acetophenone), acids (p-toluene sulphonic acid, terephthalic acid, formic acid, or acetic acid), or water, and their mixtures, the amount of the activator being 1-30% by weight based on the PET raw material.
3. The method according to claim 1, wherein the acidic hydrolysis is carried out in the presence of acidic catalysts selected from the group consisting of heterogeneous catalysts such as montmorillonites K10 and KSF, ion exchangers, zeolites, phosphoric acid supported by a carrier such as alumina or silica, furthermore, copper(II), iron(III), zinc(II), aluminum(III), antimony(III), bismuth(III) chloride or acetate, respectively, or homogeneous catalysts such as p-toluene sulphonic, formic, acetic, benzoic, terephthalic, or sulphuric acid.
4. The method according to claim 1, wherein the alkaline hydrolysis is carried out in the presence of strong bases such as alkaline metal hydroxides (sodium hydroxide, potassium or lithium hydroxide, respectively), or in the presence of phase transfer catalysts, such as TOMAB (trioctyl methyl ammonium bromide).
5. The method according to claim 1, wherein the alcoholysis is carried out in the presence of an alcohol such as methanol, ethanol, ethylene glycol and trans-esterification catalysts selected from the group consisting of zinc(II) or iron(III) chloride, respectively, or manganese(II), cobalt(II), calcium(II), and magnesium(II) acetates.
6. The method according to claim 1, wherein the depolymerization is carried out in the presence of ionic liquid added to the molten mixture in the second stage of depolymerization.
7. The method according to claim 1, wherein in the first and the second stage the depolymerization is carried out in air or an inert atmosphere of nitrogen or argon.
8. The method according to claim 1, wherein in the second stage of the depolymerization process the molten mixture is exposed to a microwave radiation at the temperature between 100 and 220° C.
9. The method according to claim 1, wherein in the first and the second stage the depolymerization is carried out in a batch or continuous process.
US12/452,630 2007-07-13 2008-07-09 Method for the chemical depolymerization of waste polyethylene terephthalate Abandoned US20100133088A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CZ20070469A CZ2007469A3 (en) 2007-07-13 2007-07-13 Method of waste polyethyleneterephthalate chemical depolymerization
CZPV2007-469 2007-07-13
PCT/EP2008/058917 WO2009010435A2 (en) 2007-07-13 2008-07-09 Method for the chemical depolymerization of waste polyethylene terephthalate

Publications (1)

Publication Number Publication Date
US20100133088A1 true US20100133088A1 (en) 2010-06-03

Family

ID=40120188

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/452,630 Abandoned US20100133088A1 (en) 2007-07-13 2008-07-09 Method for the chemical depolymerization of waste polyethylene terephthalate

Country Status (7)

Country Link
US (1) US20100133088A1 (en)
EP (1) EP2176327B1 (en)
CN (1) CN101688015B (en)
AT (1) ATE487759T1 (en)
CZ (1) CZ2007469A3 (en)
DE (1) DE602008003455D1 (en)
WO (1) WO2009010435A2 (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014035937A2 (en) * 2012-08-30 2014-03-06 Glyeco, Inc. Method and apparatus for processing glycol
JP2015036393A (en) * 2013-08-12 2015-02-23 学校法人君が淵学園 Depolymerization method of polyester and method for recovering raw ingredient monomer of polyester by using the same depolymerization method
CN104892422A (en) * 2015-05-05 2015-09-09 芜湖职业技术学院 Polyester fiber degradation method
US10259922B2 (en) 2013-11-06 2019-04-16 The Board Of Trustees Of The Leland Stanford Junior University Methods for modifying a hydrophobic polymer surface and devices thereof
US10315126B2 (en) 2013-03-14 2019-06-11 Donald W. Ramer Apparatus for molecular targeting and separation of feedstock fluids
WO2020209607A1 (en) * 2019-04-08 2020-10-15 고려대학교 산학협력단 Method for producing high value-added compounds from polyethylene terephthalate
US20210017353A1 (en) * 2018-03-12 2021-01-21 JBPV s.r.o. Method of obtaining terephthalic acid from waste polyethylene terephthalate
CN112739756A (en) * 2018-09-21 2021-04-30 普莱米尔塑料公司 Method and system for depolymerizing plastic
CN113149825A (en) * 2021-04-02 2021-07-23 华中科技大学 Method for catalytic degradation of polyethylene glycol terephthalate
WO2021163102A1 (en) * 2020-02-10 2021-08-19 Eastman Chemical Company Chemical recycling of polyolefin-containing plastic waste and solvolysis coproduct streams
WO2021257920A1 (en) * 2020-06-19 2021-12-23 Ineos Us Chemicals Company Improved catalyst performance for polyester recycling
US11479651B2 (en) * 2015-11-20 2022-10-25 The University Of North Carolina At Chapel Hill Chemical recycling of polyethylene terephthalate by microwave irradiation
WO2023163481A1 (en) * 2022-02-25 2023-08-31 에스케이케미칼 주식회사 Method for preparing recycled bis(2-hydroxyethyl) terephthalate through multi-step depolymerization

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101671232A (en) * 2009-09-30 2010-03-17 温州大学 Method for catalyzing and depolymerizing polyethylene glycol terephthalate under microwave environment
EP2561040A1 (en) * 2010-04-23 2013-02-27 Organic Fuel Technology A/S Process for the production of biofuel
CN102796002B (en) * 2011-05-27 2015-02-18 中国科学院过程工程研究所 Method for catalytically alcoholizing polyethylene terephthalate
CN103030564B (en) * 2011-10-09 2015-04-01 中国科学院过程工程研究所 Method for carrying out high-efficiency catalytic alcoholysis on polyethylene terephthalate (PET) by multi-component catalyst
CN104387928A (en) * 2014-10-22 2015-03-04 罗海军 Method for preparing powder latex paint from waste polycarbonate
CZ2014945A3 (en) * 2014-12-22 2016-02-24 Vysoké Učení Technické V Brně Process for preparing secondary polyols and use thereof
CN104878598B (en) * 2015-06-11 2017-07-14 中原工学院 A kind of microwave radiation technology ammonolysis method of surface hydrophilic terylene
CN106866413A (en) * 2017-01-11 2017-06-20 西安工业大学 A kind of method that efficient cryogenic reclaims Waste Polyester PET
CN109734573A (en) * 2019-01-11 2019-05-10 中国科学院过程工程研究所 A kind of method that ionic liquid composite catalyst catalyzing hydrolysis PET prepares PTA
CN110172140B (en) * 2019-05-19 2023-11-24 福建师范大学 Method for preparing unsaturated polyester resin by hydrolyzing waste polyester textile fabric with microwaves
CN110483279B (en) * 2019-07-10 2020-08-14 艾凡佳德(上海)环保科技有限公司 Method for recovering waste polyester material
CN110527138B (en) * 2019-07-10 2020-07-03 艾凡佳德(上海)环保科技有限公司 Continuous alcoholysis recovery method of waste polyester
CN110511137B (en) * 2019-07-10 2020-06-26 艾凡佳德(上海)环保科技有限公司 Continuous alcoholysis and ester exchange recovery method for waste polyester material
CN110368971B (en) * 2019-08-09 2022-01-28 陕西科技大学 SiC-based composite catalyst for microwave-assisted depolymerization of solid waste and preparation method thereof
CN110368972B (en) * 2019-08-09 2022-01-28 陕西科技大学 Core-shell SiC @ C catalyst for microwave-assisted catalytic depolymerization of solid waste and preparation method thereof
EP4136160A1 (en) * 2020-04-13 2023-02-22 Eastman Chemical Company Chemical recycling of waste plastics from various sources, including wet fines
MX2022012763A (en) * 2020-04-13 2022-10-31 Eastman Chem Co Chemical recycling of plastic dry fines.
CN113173856A (en) * 2021-03-29 2021-07-27 中国科学院青岛生物能源与过程研究所 Method for catalytic degradation of waste polyester material by using zinc catalyst
CN113897628B (en) * 2021-08-27 2023-04-18 中国科学院理化技术研究所 Method for electrolyzing and depolymerizing PET (polyethylene terephthalate) by using electrocatalysis
CN114031756B (en) * 2021-10-13 2022-08-26 国高材高分子材料产业创新中心有限公司 Method for preparing recycled polyester by closed-loop recycling waste polyester with typical green low-carbon characteristics
CN114773197A (en) * 2022-03-11 2022-07-22 中国科学院青岛生物能源与过程研究所 Method for recycling PET (polyethylene terephthalate) mixed plastic
CN116102782A (en) * 2023-02-24 2023-05-12 西湖大学 Recovery processing method of PET plastic waste, regenerated PET plastic and application

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2865892A (en) * 1953-09-30 1958-12-23 Du Pont Process for stabilizing molten polyethylene terephthalate
US3544622A (en) * 1965-03-10 1970-12-01 Du Pont Alkaline saponification of polyethylene terephthalate at high temperatures using controlled amount of sodium hydroxide
US4355175A (en) * 1981-04-06 1982-10-19 Pusztaszeri Stephen F Method for recovery of terephthalic acid from polyester scrap
US4605762A (en) * 1982-04-23 1986-08-12 Celanese Mexicana S.A. Depolymerization of condensation polymers
US5559159A (en) * 1995-12-07 1996-09-24 Eastman Chemical Company Process including depolymerization in polyester reactor for recycling polyester materials
US6184427B1 (en) * 1999-03-19 2001-02-06 Invitri, Inc. Process and reactor for microwave cracking of plastic materials
US6368994B1 (en) * 1999-12-27 2002-04-09 Gyrorron Technology, Inc. Rapid processing of organic materials using short wavelength microwave radiation
US20030032840A1 (en) * 2000-03-17 2003-02-13 Milan Sirek Method of chemical recycling of polyethylene terephthalate waste
US6670503B2 (en) * 2000-02-29 2003-12-30 Massimo Broccatelli Method for recovery of terephthalic acid from a material containing poly(ethylene terephthalates)
US6720448B2 (en) * 2000-10-11 2004-04-13 Massimo Broccatelli Method of recovering chemical species by depolymerization of poly (ethylene terephthalate) and related use
US20050096482A1 (en) * 2002-02-01 2005-05-05 Ryozo Tamada Method of depolymerizing polyethylene terephthalate and process for producing polyester resin
US20070131591A1 (en) * 2005-12-14 2007-06-14 Mobilestream Oil, Inc. Microwave-based recovery of hydrocarbons and fossil fuels
US20090318579A1 (en) * 2005-12-09 2009-12-24 Kumamoto Technology And Industry Foundation Method for Depolymerizing Polyester and Unsaturated Polyester, and Method for Recovering Polyester Monomer Using the Depolymerization

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2697839B1 (en) 1992-11-09 1995-01-13 Inst Francais Du Petrole Improved process for recovering alkali metal terephthalate and alkylene glycol from polyalkylene terephthalates.
SI9800060A (en) * 1998-03-02 1999-10-31 Kemijski Inštitut, Ljubljana Solvolysis of polyethyleneterephthalate with the use of micriwaves as the source of energy
CN1401688A (en) * 2002-09-15 2003-03-12 中国科学院兰州化学物理研究所 Process of chemical recovery of waste polyglycol p-phthalate
CN1239461C (en) * 2004-06-17 2006-02-01 温州师范学院 Microwave depolymerization method for PET
CZ296280B6 (en) 2004-10-13 2006-02-15 Sírek@Milan Process of chemical recycling waste polyethyleneterephthalate
CZ296343B6 (en) * 2004-10-21 2006-02-15 Výzkumný ústav pro hnedé uhlí a. s. Physical-chemical recycling process of waste polyethyleneterephthalate
CN101066905A (en) * 2007-06-06 2007-11-07 温州大学 Catalytic depolymerization of PET under microwave irradiation

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2865892A (en) * 1953-09-30 1958-12-23 Du Pont Process for stabilizing molten polyethylene terephthalate
US3544622A (en) * 1965-03-10 1970-12-01 Du Pont Alkaline saponification of polyethylene terephthalate at high temperatures using controlled amount of sodium hydroxide
US4355175A (en) * 1981-04-06 1982-10-19 Pusztaszeri Stephen F Method for recovery of terephthalic acid from polyester scrap
US4605762A (en) * 1982-04-23 1986-08-12 Celanese Mexicana S.A. Depolymerization of condensation polymers
US5559159A (en) * 1995-12-07 1996-09-24 Eastman Chemical Company Process including depolymerization in polyester reactor for recycling polyester materials
US6184427B1 (en) * 1999-03-19 2001-02-06 Invitri, Inc. Process and reactor for microwave cracking of plastic materials
US6368994B1 (en) * 1999-12-27 2002-04-09 Gyrorron Technology, Inc. Rapid processing of organic materials using short wavelength microwave radiation
US6670503B2 (en) * 2000-02-29 2003-12-30 Massimo Broccatelli Method for recovery of terephthalic acid from a material containing poly(ethylene terephthalates)
US20030032840A1 (en) * 2000-03-17 2003-02-13 Milan Sirek Method of chemical recycling of polyethylene terephthalate waste
US6720448B2 (en) * 2000-10-11 2004-04-13 Massimo Broccatelli Method of recovering chemical species by depolymerization of poly (ethylene terephthalate) and related use
US20050096482A1 (en) * 2002-02-01 2005-05-05 Ryozo Tamada Method of depolymerizing polyethylene terephthalate and process for producing polyester resin
US20090318579A1 (en) * 2005-12-09 2009-12-24 Kumamoto Technology And Industry Foundation Method for Depolymerizing Polyester and Unsaturated Polyester, and Method for Recovering Polyester Monomer Using the Depolymerization
US20070131591A1 (en) * 2005-12-14 2007-06-14 Mobilestream Oil, Inc. Microwave-based recovery of hydrocarbons and fossil fuels

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014035937A3 (en) * 2012-08-30 2014-04-17 Glyeco, Inc. Method and apparatus for processing glycol
GB2519031A (en) * 2012-08-30 2015-04-08 Glyeco Inc Method and apparatus for processing glycol
US9145345B2 (en) 2012-08-30 2015-09-29 Glyeco, Inc. Method and apparatus for processing glycol
WO2014035937A2 (en) * 2012-08-30 2014-03-06 Glyeco, Inc. Method and apparatus for processing glycol
US10315126B2 (en) 2013-03-14 2019-06-11 Donald W. Ramer Apparatus for molecular targeting and separation of feedstock fluids
JP2015036393A (en) * 2013-08-12 2015-02-23 学校法人君が淵学園 Depolymerization method of polyester and method for recovering raw ingredient monomer of polyester by using the same depolymerization method
US10259922B2 (en) 2013-11-06 2019-04-16 The Board Of Trustees Of The Leland Stanford Junior University Methods for modifying a hydrophobic polymer surface and devices thereof
CN104892422A (en) * 2015-05-05 2015-09-09 芜湖职业技术学院 Polyester fiber degradation method
US11479651B2 (en) * 2015-11-20 2022-10-25 The University Of North Carolina At Chapel Hill Chemical recycling of polyethylene terephthalate by microwave irradiation
US20210017353A1 (en) * 2018-03-12 2021-01-21 JBPV s.r.o. Method of obtaining terephthalic acid from waste polyethylene terephthalate
CN112739756A (en) * 2018-09-21 2021-04-30 普莱米尔塑料公司 Method and system for depolymerizing plastic
WO2020209607A1 (en) * 2019-04-08 2020-10-15 고려대학교 산학협력단 Method for producing high value-added compounds from polyethylene terephthalate
KR20200119213A (en) * 2019-04-08 2020-10-19 고려대학교 산학협력단 Synthesis of high-value products from polyethylene terephthalate
KR102596398B1 (en) * 2019-04-08 2023-11-02 고려대학교 산학협력단 Synthesis of high-value products from polyethylene terephthalate
WO2021163102A1 (en) * 2020-02-10 2021-08-19 Eastman Chemical Company Chemical recycling of polyolefin-containing plastic waste and solvolysis coproduct streams
WO2021257920A1 (en) * 2020-06-19 2021-12-23 Ineos Us Chemicals Company Improved catalyst performance for polyester recycling
CN113149825A (en) * 2021-04-02 2021-07-23 华中科技大学 Method for catalytic degradation of polyethylene glycol terephthalate
WO2023163481A1 (en) * 2022-02-25 2023-08-31 에스케이케미칼 주식회사 Method for preparing recycled bis(2-hydroxyethyl) terephthalate through multi-step depolymerization

Also Published As

Publication number Publication date
ATE487759T1 (en) 2010-11-15
WO2009010435A2 (en) 2009-01-22
CN101688015A (en) 2010-03-31
EP2176327A2 (en) 2010-04-21
EP2176327B1 (en) 2010-11-10
CZ299908B6 (en) 2008-12-29
CN101688015B (en) 2012-09-19
CZ2007469A3 (en) 2008-12-29
WO2009010435A3 (en) 2009-03-12
DE602008003455D1 (en) 2010-12-23

Similar Documents

Publication Publication Date Title
EP2176327B1 (en) Method for the chemical depolymerization of waste polyethylene terephthalate
JP7071526B2 (en) Recovery method of waste polyester by continuous alcohol decomposition
US7462649B2 (en) Method for recycling pet bottle
JP7071528B2 (en) How to collect waste polyester material
KR100746678B1 (en) Dimethyl terephthalate composition and process for producing the same
EP3765559B1 (en) Method of obtaining terephthalic acid from waste polyethylene terephthalate
CN109134244A (en) A kind of biodegrading process of waste and old polyester
KR100693707B1 (en) The method of chemical recycling of polyethylene terephthalate waste
WO2003101929A1 (en) Processes for the purification of bis(2-hydroxyethyl) terephthalate
JP4212799B2 (en) Method for recovering terephthalic acid from polyester fiber waste
JP5178211B2 (en) Method for recovering dimethyl terephthalate with improved hue from PET bottle waste
CN114230857A (en) Method for rapidly degrading PET through high-temperature swelling effect
JP2002167468A (en) Recovery method of active ingredient from polyester film scrap
JPH09249597A (en) Recovery of monomer from aromatic polyester
JP3894426B2 (en) Reuse method of recovered polyester
JP4163842B2 (en) Method for recovering dimethyl terephthalate from polyethylene terephthalate
JP2011098904A (en) Manufacturing method of dimethyl terephthalate from polyester
TW528773B (en) Dimethyl terephthalate composition and process for producing the same
CN117700320A (en) Method for depolymerizing waste polyester by adopting double depolymerization method
JP2012116912A (en) Method for producing polyester monomer from polyester
JP2004284022A (en) Method for crushing polyester waste
JP2002161064A (en) Terephthalic acid composition
JP2001039908A (en) Continuous production of monomers from aromatic polyester
WO2008047651A1 (en) Process for production of flake-like dried 2-(5-ethyl-5-hydroxymethyl-1,3-dioxan-2-yl)-2-methylpropan-1-ol
JP2003128600A (en) Method for producing terephthalic acid from waste bottle

Legal Events

Date Code Title Description
AS Assignment

Owner name: USTAV CHEMICKYCH PROCESU AKADEMIE VED CESKE REPUBL

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HAJEK, MILAN;SOBEK, JIRI;BRUSTMAN, JAROSLAV;REEL/FRAME:023830/0214

Effective date: 20091228

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION